title: An algorithmic approach to mechanical hip pain.
abstract: BACKGROUND
  As our understanding of hip pathology evolves, the focus is shifting toward earlier identification of hip pathology. Therefore, it is vitally important to elucidate intra-articular versus extra-articular pathology of hip pain in every step of the patient encounter: history, physical examination, and imaging.
  
  
  OBJECTIVE
  The objective was to address the following research questions: (1) Can an algorithmic approach to physical examination of a painful non-arthritic hip provide a more accurate diagnosis and improved treatment plan? (2) Does an anatomical layered concept of clinical diagnosis improve diagnostic accuracy? (3) What are the diagnostic tools necessary for the accurate application of a four-layer (osteochondral, inert, contractile, and neuromechanical) diagnosis?
  
  
  METHODS
  An unrestricted computerized search of MEDLINE was conducted. Different terms were used in various combinations.
  
  
  RESULTS
  An algorithmic approach to physical examination of a painful nonarthritic hip, including history, physical examination (specific tests), and advanced imaging allow for better interpretation of debilitating intra- and extra-articular disorders and their effect on core performance. Additionally, it improves our understanding as to how underlying abnormal joint mechanics may predispose the hip joint and the associated hemipelvis to asymmetric loads. These abnormal joint kinematics (layer I) can lead to cartilage and labral injury (layer II), as well as resultant injury to the musculotendinous (layer III) and neural structures (layer IV) about the hip joint and the hemipelvis. The layer concept is a systematic means of determining which structures about the hip are the source of hip pathology and how to best implement treatment.
  
  
  CONCLUSIONS
  A clear understanding of the differential diagnosis of hip pain through a detailed and systematic physical examination, diagnostic imaging assessment, and the interpretation of how mechanical factors can result in such a wide range of compensatory injury patterns about the hip can facilitate the diagnosis and treatment recommendations.
authors.affiliation: Department of Orthopaedic Surgery, Center for Hip Pain and Preservation, Hospital for Special Surgery, 535 East 70th street, New York, NY 10021 USA.
authors.forename: Lazaros A
authors.initials: LA
authors.lastname: Poultsides
authors.forename: Asheesh
authors.initials: A
authors.lastname: Bedi
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Kelly
keywords: extra-articular hip pathology; hip pain; intra-articular hip pathology; mechanical hip pain; physical examination of the hip joint